You probably don't have the latest QEMU and need to edit the hackintosh.xml. Replace pc-i440fx-3.1 with pc-i440fx-2.9. Then make a backup of the QEMU-VARS.fd, delete the virtual device, restore the backup, and import the XML file again.
Yes. Add two devices: Graphics and Video. Set Video to Virtio, disable 3D acceleration. Set Display to Spice, set listen type to None.
One more thing they don't tell you: before you start the installation, you need to create a third storage medium where the actual OS will be installed. Make a SATA device with at least 60 GB.